Vapor samples are analyzed from biological sources for various purposes. For example, breath samples are taken and analyzed to determine whether the subject has recently consumed alcoholic beverages or to diagnose certain diseases.
Sulfur compounds have been detected by chemiluminescence reaction with ozone. A typical technique, used, for example, in the bottle industry, involves burning the sample in the presence of a metal catalyst and a reducing agent, such as hydrogen, to produce H.sub.2 S or SO. These compounds are reacted with ozone to produce SO.sub.2 which is luminescent and can thus be detected.
Gas chromatography is a technique in which a mixture of unknown chemical compounds is carried by a flow of inert gas through a column that has been coated with a polymer. The chemical compounds become separated spatially along the column because of their differing affinities for the column of polymer. Generally, higher molecular weight, less volatile compounds are retained to a greater extent than lower molecular weight, more volatile compounds. The compounds emerge from the column in sequence and can be detected and identified. To optimize the analysis, the polymer material can be selected for retention of different types of compounds. The temperature of the column can also be varied during the analysis.